With the development of an input technique and a display technique, the combination of a common LCD device and a handwriting input device is a development trend meeting the market requirements.
In the prior art, the technical solutions which facilitate the LCD device to have a handwriting input function have the following forms. Firstly, according to realization principles, the handwriting input can be divided into a resistance type, a capacitance type and an electromagnetic induction type. The resistance type handwriting input device and the capacitance type handwriting input device can receive input signals by identifying touch actions. Generally, an independent resistance type handwriting input board or an independent capacitance type handwriting input board is assembled on the front side of the LCD device, i.e., on the side of the LCD device orientated towards the viewer, so as to receive the touch input actions. An electromagnetic induction type handwriting board identifies an input position through receiving an electromagnetic signal of an electromagnetic induction pen. Generally, the electromagnetic induction type handwriting board is also assembled on the front side of or the back side of the LCD device as one independent device, for example, it is assembled on the back side of a backlight module.
The above technical solutions for realizing the handwriting input function of the LCD device have the following defects. The thickness of the LCD device is increased due to the handwriting input board being as one independent device, which does not conform to the light and thin development trend of the LCD device. When assembled, the handwriting input board and the LCD device have the problems of unstable and unreliable assembly, thus causing input accuracy to be decreased. As for the electromagnetic induction type handwriting input board, when it is assembled on the back side of the LCD device, the thicknesses of an LC panel and the backlight module between the input board and the electromagnetic induction pen influence the identification of the electromagnetic signals and decreases input accuracy.